History of cigarette smoking and heart transplant outcomes

Background: Active cigarette smoking (CS) is a contraindication for Orthotopic Heart Transplantation (OHT) with a recommendation that HT candidates be free from CS for at minimum 6 months prior to HT. Animal studies have shown that a history of CS is associated with increased risk of allograft rejection, but few studies have examined the association of past CS and HT outcomes. Methods: Data were analyzed from HT recipients captured in the United Network for Organ Sharing (UNOS) transplant registry. Adults aged 18–79 who underwent HT from 1987 to 2018 and with data for all covariates (N = 32,260) were included in this study. The cohort was categorized by past smoking history (CS vs non-CS). Post-transplant outcomes of interest included survival, graft failure, treated rejection, malignancy and hospitalization for infection. Baseline characteristics were compared between the two groups using the chi-squared analysis. Unadjusted associations between CS and patient survival were determined using the Kaplan-Meier estimations and confounding was addressed using multivariable Cox proportional hazards models. Results: HT recipients with a history of CS were older (55 vs 50, p = <0.0001), more likely to be Caucasian (75.7 vs 62.3, p = <0.0001), male (81.7 vs 68.2, p =< 0.0001), and diabetic (27.4 vs 24.4, p =< 0.0001). CS was associated with significantly worse survival (HR: 1.23, p < 0.0001). A history of CS was also associated with increased risk of acute rejection (OR: 1.20, p < 0.0001), hospitalization for infection (OR:1.24, p < 0.0001), graft failure (OR:1.23, p < 0.0001) and post-transplant malignancy (OR:1.43, p < 0.0001). Conclusion: A history of CS is associated with increased risk of adverse events post OHT.

HLA frequencies in Pakistani population groups

HLA Antigen A, B and DR frequencies were determined in 912 subjects who were prospective donors and recipients for renal transplantation. Of the 912, 305 were Sindhi, 248 Punjabi, 315 Urdu and 44 Pushto speaking. HLA A1, A2, A11 and A19 were common in all these groups. A3 was more frequent in Pushto, A9 (24) in Punjabi, A10 (26) in Sindhi and A28 in Urdu-speaking group. HLA B5 (51) and B40 (60) were common in all, while B8 in Sindhi and Punjabi, B35 in Sindhi, Urdu and Pushto and B27 in Punjabi and Urdu speaking individuals. HLA-DR3 and DR2 (15) were common in all groups. DR6 (13) in Sindhi, Urdu and Pushto and DR6 (14) in Punjabi, DR5 (11) in Urdu, Punjabi and Pushto speaking subjects. Overall, Pakistani frequencies showed linkage to Caucasians and Orientals. This paper describes differences in frequencies in various population groups within Pakistan which may have relevance in factors where HLA system plays a crucial role.